245/60R18 vs 275/60R18
275/60R18 is outside the ±3% rule as a replacement for 245/60R18: the diameter differs by +4.79%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 275/60R18 on a car calibrated for 245/60R18, the speedometer reads 57.3 mph when you're really doing 60, and the odometer under-counts by 4.8%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.4 mph |
| 45 mph | 47.2 mph |
| 60 mph | 62.9 mph |
| 70 mph | 73.4 mph |
| 80 mph | 83.8 mph |
Other sizes close to 245/60R18
- 245/60R18 vs 235/60R18-1.60%
- 245/60R18 vs 235/55R18-4.73%
- 245/60R18 vs 265/60R18+3.19%
- 245/60R18 vs 225/60R18-3.19%
- 245/60R18 vs 245/65R17-0.12%
- 245/60R18 vs 255/55R18-1.80%
- 245/60R18 vs 235/65R18+1.53%
- 245/60R18 vs 245/55R19+0.12%
- 245/60R18 vs 255/65R18+4.99%
- 245/60R18 vs 265/50R19-0.48%
- 245/60R18 vs 255/60R18+1.60%
- 245/60R18 vs 245/55R18-3.26%
Questions
Can I replace 245/60R18 with 275/60R18?
275/60R18 is outside the ±3% rule as a replacement for 245/60R18: the diameter differs by +4.79%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 245/60R18 and 275/60R18?
275/60R18 is 1.42" taller and 30 mm wider; the sidewall is +0.71". At an indicated 60 mph you'd actually be doing 62.9 mph.
Will 275/60R18 fit on 245/60R18 wheels?
Both use a 18" rim, so the wheel diameter matches; check the wheel's width range for a 275 mm tire and the fender clearance.